The esterolytic antibody 48G7 binds its phosphonate hapten 31,000 times more tightly than its germline antibody. The mature antibody contains nine amino acids that are different from the corresponding amino acids in the germline molecule. None of these somatic mutations contact the hapten. We are using molecular dynamics and continuum solvent methods to gain insight into the difference in the binding free energies of the mature and germinal antibody complexes. The molecular visualization software packages offered by the Computer Graphics Laboratory (i.e., MidasPlus) have been useful tools for the research.